Group CMake config changes.
Group CMake config changes.

Group and sort the CMake configuration changes in
aom_configure.cmake, and make sure everything that
changes a CONFIG_ variable is taken care of before
inclusion of cpu.cmake (which controls the RTCD
versions of the CONFIG_ vars).

Change-Id: Ib8069721de63c332392b7216fe3f194a077eb73c

GrokImageCompression/aom,GrokImageCompression/aom,GrokImageCompression/aom,GrokImageCompression/aom,GrokImageCompression/aom,GrokImageCompression/aom